The developers estimate the developments will support up to 4,600 jobs during peak construction and up to 580 jobs once in operation.

In total, the plans will deliver up to 326 wind turbines, and consent has been granted subject to strict conditions on the impact of the development, including in relation to birds and other environmental considerations.

When operational, the developments off the Caithness coast are estimated will generating up to 1,866 MW of electricity, enough to power over one million homes.

The developments are also estimated will be worth up to £2.5 billion to the Scottish economy.

Mr Ewing said: “Scotland has the potential to lead the development of an exciting, new renewables industry as offshore wind moves into deeper waters. Offshore renewables represent a huge opportunity for Scotland; an opportunity to build up new industries and to deliver on our ambitious renewable energy and carbon reduction targets.

“These wind farms alone could generate gross value worth up to £2.5 billion over their lifetime and generate up to 4,600 jobs during peak construction and up to 580 once in operation.

“Offshore wind has been delayed by the process of the UK Government’s Electricity Market Reform, but these two consents today offer tangible progress towards real investment opportunity in Scotland.”

Lindsay Leask, senior policy manager for the trade body, Scottish Renewables, said: "We are delighted to finally see the first ever consent being granted for a large scale commercial offshore wind farm in Scotland.

"This is a really important step forward for the industry, which has the potential to generate massive amounts of renewable power and support significant numbers of new jobs.”

She added: “The big focus now moves on to whether or not these projects can access a Contract for Difference - the new support mechanism for nuclear, renewables and carbon capture and storage - which the backers of the projects need to finalise their investments.”